This invention relates to the art of welding and, more particularly, to the encoding of metal welding wire with information pertaining thereto, and to the monitoring and/or controlling of automatic or semi-automatic welding apparatuses and processes based on the information extracted from a coded welding wire. The present invention is particularly applicable to the encoding and use of coded welding wire in connection with controlling automatic or semiautomatic arc welding apparatuses and processes based on information pertaining to the welding wire. Accordingly, the invention will be described with reference to such welding wire information in conjunction with manual and/or automatic control of a welding process or apparatus.
Electric arc welding is a complicated process wherein numerous interrelated and non-interrelated parameters affect the deposition of molten metal to a weld pool when performing a welding operation. One such parameter is the welding wire to be used and, in particular, information pertaining thereto which is useful, for example, in determining processes and apparatuses in which its use is best suited and processes and/or apparatus operating parameters for a given wire. In addition, information such as, but not limited to, the alloy type, wire diameter, control numbers, lubrication levels, and the like is valuable for controlling a given process or apparatus so as to optimize performance and weld quality.
One factor affecting weld quality is welding wire feed speed. The welding process takes into account the speed of the electrode in determining the required welding current and/or voltage. The electrode or wire feed speed is normally controlled by a wire feeder apparatus. An integral part of the wire feeder apparatus is a means of measuring the wire feed speed. This signal is applied to a control circuit which compares it to the “wire feed speed” command signal. The output of this control circuit controls the speed of the wire drive motor such that the signal proportional to the wire feed speed is essentially equal to the wire feed speed command. A tachometer is normally employed for measuring the wire speed. This mechanical device includes a wheel or wheels which contact the moving wire. Attached to the wheels is normally a magnet or sets of magnets. As these magnets rotate, they pass by a coil, in which an electrical signal is induced. The frequency of this signal is related to the speed of the wire. Other types of tachometers are also available such as, but not limited to, optical designs which use a beam of light passing through a disk with slits. If the speed of the welding wire is not properly detected, the quality of the formed weld bead is seriously compromised. For instance, if slippage occurs through the drive wheels and/or if dirt, dust, etc. interferes with an optical speed detector, the improper welding wire feed speed will be detected thereby potentially resulting in a low quality weld bead being formed. An unsatisfactory weld bead on a product can result in having to dispose of such products, thus adversely affect the efficiency of the welding process and increasing the costs associated with the lost or unacceptable product. Still another factor affecting weld quality and/or the efficiency of the welding process is the amount of a consumable that remains during a welding process. Consumables such as, but not limited to, the welding wire are consumed during a welding process. During an automatic or semi-automatic welding process, the welding process may not be closely monitored by an operator. As such, the welding wire may be used up during a welding process thereby adversely affecting the weld quality. For instance, when the weld wire is fully consumed, further formation of a weld bead does not occur. In addition, when the welding wire is fully used, the welding operation has to ultimately stop and the consumable must be replaced. The stopping of the welding process reduces welding efficiencies due to unanticipated down time and can also result in partially welded workpieces having to be discarded.
In view of the state of the prior art, there is a need for a welding monitoring and/or control system to improve the efficiencies of automatic and/or semi-automatic welding processes and the quality of a formed weld bead.